Dynamo-electric machine.



No. 854,704. PATENTED MAY 21, 1907.

W. J, RICHARDS.

DYNAMO ELECTRIC MACHINE. APPLICATION FILED AUG. 27. 1906.

UNITED STATES WALTER J. RICHARDS, OF N ORWOOD,

COMPANY, A CORPORATION OF NEW JERSEY, AND

PATENT OFFICE.

OHIO, ASSIGNOR TO ALLIS-CHALMERS THE BULLOCK ELEC- TRIC MANUFACTURING COMPANY, A CORPORATION OF OHIO.

To all whom it may concern.-

Be it known that I, WALTER J. RICHARDS, a citizen of the- United States, residing at Norwood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Dynamo-Electric Machines, of which the following is a full,- clear, and exact specification.

My invention relates to dynamo-electric machines provided with means for preventing sparking at the commutators.

Anti-sparking windings for dynamo-electric machines are usually connected in series with the armature so that the current variations in them and in the armature are proportional. Howevenit is sometimesdesirable that the current in the anti-sparking windingsvary in a diiierent ratio from the 1 current in the armature, and this is especially so when the machine is being operated near its maximum load, where due to the knee in the saturation curve the effective magnetization due to the anti-sparking winding rises more-slowly than the current. For this reason'in order to have the spark-reducing magnetization vary in proportion to the armature current, it is desirable to have the current in the anti-sparking windings vary proportionatelymore rapidly than the armature current, and thismy invention is intended to accomplish. And it is sometimes desirable to have this magnetization varyin some other than direct proportion with the armature current." This also can be accomplished by my invention. 'If desired my invention can also be, applied toxdistributed compensating windings, though it is here especially described in connection with concentrated commutating windings wound on auxiliary poles.

' In one aspect my invention consists of a dynamo-electric machine having main and anti-sparking field windings, and means for causing the current in the anti-sparking winding to vary in greater proportion than the main current.-

. In a more specific aspect my invention consists of a dynamo-electric machiie comprising an armature, a main field winding, and a commutating winding in series with the armature, and resistances in series and in shunt respectively to the commu'tating winding and arranged to be varied with the. varia- Specification of Letters Patent. 7 Application filed August 27, 1906. erial No. 832,087.

Patented May 21, 1907.

[ tion in the main current to cause the current in the commutating Winding to rise and fall rent in the armature winding.

Other features of my invention will appear from the description and drawings and will be particularly pointed out in the claims.

Figure 1 is a view showing one embodi- I ment of my invention; and Figs. 2, 3 and 4 are simple diagrams showing modifications.

Referring first to Fig. 1, is thearmature and 11 the field frame. of a dynamo-elcctric machine. The field framecarries main poles 1-2 and 13 and auxiliary poles 14 and 15. These auxiliary poles are now commonly known as commutating poles and serve to reverse the current in the armature coil undergoing commutation in a manner so well here necessary. On the main field poles 12 and 13 is the main field winding 16, here shown as a shunt winding and as being adjustable by the rheostat 17. On the ccmmutating poles is a series winding 18. This winding has in series therewith a resistance 19 of carbon or other material having a negative temperature coel'licient of resistance, while in shunt to the Winding 18 and the resistance 19 is a positive temperature coefficient of resistance. If desired, the resistances 19 and 20 may be made of materials which both have either positive or negative temperature coeiiicients of resistances, it being only neces sary that this coefficient ofthe resistance 19 ance 20. The resistance 20 is shown as ad justable The operation of the arrangement shown rent the resistances 19 and 20 are heated whereupon the resistance of 19 decreases and that of 20 increases and that branch of the circuit containing the. resistance 19 and commutating winding 18 takes a larger share of the wholevcurrent than it previously had and the branch which contains the resistance 20 takes a smallershare thereof. Thecurrent in the commutating winding 18 thus rises in greater ratio than the main crarmaturec'urrent, causing the magnetization of the auxiliary poles 14 and 15, by reason of the knee I in their magnetization curvefto increase in I known that no explanation of their action is resistance 20 of iron or other. material having be algebraically less than that of the resistin Fig. 1 is as-follows:Upon a rise in our approximately the same ratio as the main current. By properly adjusting the resistances 19 and the magnetization of these auxiliary poles may be made to increase in the same ratio as the main current, or in a greater or less ratio as'desired.

In the modification shown in Fig. 2 the main field winding 16 is in series with the armature 10 and is adjustable by means'of the resistance 17 in shunt to it instead of in series with it as in. Fig. 1. The commutating winding 18 is in series with the armature, and its terminals are connected to the terminals of a resistance 21. From a variable intermediate point of the resistance, the current proceeds through the arm 22 and the solenoid 23 to the line. Upon an increase in the current the solenoid 23 which carries the full armature current draws the arm 22 to the right and decreases the portion of the resistance 21 in series with the commutating winding 18 and increases the portion in shunt thereto, thus increasing the proportionate part of the main current which flows through the commutating winding. The action of the solenoid 23 on the arm 22 is opposed by a spring 24 which. on decrease of current draws the arm 22 to the left to cause the ratio between the current in the commutating winding and the main current to decrease.

In Fig. 3 the main field winding 16 is in shunt to the armature, in Fig. 1, and is adjustable by means oi the variable resistance 17". The armature 1O has in series there with the commutating winding 18 This winding is in series with a pile of carbon blocks 25, In shunt to the winding 18 and the carbon blocks 25 is a resistance 26 which may be adjustable, but after adjustment may remain approximately constant or may vary as the current through it varies. Upon a rise in the armature current the solenoid 27 compresses the pile of carbon blocks 25 and causes a greater part of the main current to flow through the commutating winding 18*, thus varying the strength of the commutating poles in approximate proportion to the main current. In Fig. 3 when the device is used as a motor, the solenoid 27 carries only the armature current, as the variation in the iiel d current does not directly require a varia tion in the commutating pole strength as do the controlling means in Figs. 2 and 4:.

In Fig. 4, as in Figs. 1 and 3,the main field winding 16 is a shunt winding and is adjustable by.a rheostat 17 In this figure, however, the main field winding is connected directly in shunt to the armature 10. The

commutating winding 18 has in series, there-' with a pile of carbon bloeks 28 and in shunt thereto the adjustable resistance 29. The parts of the total current which pass through the branches'of the circuit 18 and 28, and 29, rejoin ati30, and continue through a resistance bar 31'.

blocks 28 are held in a frame 32 but insulated therefrom. Upon an increase in current, the resistance bar 31 is heated and expands, thus compressing the pile of carbon blocks" 28 so that the branch including the commutating winding 18 carries a greater share ofzthe total main current.

My invention is applicable to both generators and motors. When used in a motor a starting resistance 33 may be used as indicated in Fig. 3.

Instead of using a commutating winding, other forms of anti-sparking windings may be used. This and many other niodilications may be made in the specific structure here shown and described, and in the following claims I aim to cover all such which fall within the spirit and scope of my invention.

What I claim is 1. A dynamo electric machine having main and commutating windings, and meanstor causing the current strength in the commutating windings to vary in greater proportion than. the main current.

2. In a dynamo-electric machine, an armature, main and commutating windings, and resistances in shunt and in series respectively to the commutating winding.

3. In a dynamo-electric machine, an armature, main and commutating windings, and resistances in shunt and in series respectively to the commutating winding and arranged to be varied to cause the current in the commutating winding to vary in greater ratio than the main current.

4. In a dynamo-electric machine, the combination of main and anti-sparking windings,

and a shunt about the anti-sparking winding which increases in resistance as the main current rises.

5. A dynamo-electr1c machine having main and anti-s arking windings, and means for automatical y diverting current from the anti-s arking winding at a rate le'ss than the 1 rate 0 variation of load on the machine.

6, A dynamo -electric machine having main and commutating field coils, and means for automatically varying the current passing through the commutating coil at a rate greater than the rate of change ofload onthe machine. U

7. In combination, adynamo-clectric machine having a commutating winding, aresistance in series with the commutating winding thereof, and a shuntnbout said com-" mutating winding and resistance; v 8. In combination, a dynamo-electncmachine having an anti-sparkingwinding, .a

variable resistance in series withsaidantisparking winding, and a shuntaboutsai-d anti-s arkin winding and resistance 9. n com, ination, a dynamo-electric machine havin an anti sparking winding, an automatical y variable. resistance in series The bar 31and the carbon lwith the anti-sparking iwinding thereoi, and

an adjustable shunt around said anti-sparking. windingand resistance.

10. In combination, a dynamo electric machine provided with a commutating winding, a resistance in series with the commutating winding thereof which automatically decreases upon an increase of the main current, and a shunt about said commutati'ng winding and resistance.

11. The combination with a dynamo-elecof a resistance in series with the commutating winding thereof, and a shunt about said commutating winding and resistance which automatically increases in resistance value with an increase in the main current.

12. The combination of a dynamo-electric machine having an anti-sparking winding, a resistance in series with the anti-s arking winding thereof which .automatica 1y de creases upon an increase of the main current, and a shunt about. said anti-sparking winding and resistance which automatically in--,

creases in resistance value with an increase in the mam current.

13. in combmatlon, a dynamo-electric machine having an anti-sparking winding,

and means for varying the current in said anti-sparking winding in a ratio different from that of the main current.

14. A dynamo-electric machine having main and commutating field windings, and means for causing the ratio between the current-in the armature and that in the commutating winding to vary as the armature current varies.

15. A dynamo-electric machine having main and commutating field windings, and

means for decreasing the ratio between the current in the, armature and that in the commutating winding as the armature current increases.

16. A dynamo -electric machine having the anti-sparking winding. tric machine having a commutatmg winding,

main and anti-sparking field windings, and

that in the armature as the armature current decreases.

17. A dynamo-electric machine having main and anti-sparking field windings, and means. for automatically varying the reportionate part of the main current ta en by 18. A dynamo-electric machine having main and anti-sparking field windin s, and means for automatically increasing theproportionate part ,ofthe main current taken by the anti-sparking. winding as the load increases.

' 19. A dynamo-electric machinehaving main and commutating field wlndm s, and means forautomatically decreasing t e pro-.

- portionate part of the main current taken by the commutating Winding as the current load decreases.

20. A dynamo-electric machine having main and anti-sparking windings, and means for causing the current in the anti-sparking Winding to vary proportionately more rapidly than the main current.

21. A dynamo-electric machine having main and anti-s arking windings, and means for increasing 1; e rate of change of current in the anti-sparking winding as the armature current increases.

22. A dynamo-electric machine having main and commutating field windings, and means for decreasing the rate of change of current in the commutating winding as the main current decreases. I

Iii-testimony whereof I aifix mysignature, in the presence of two witnesses.

WALTER J. RICHARDS.

lVitnesses; Y

RUBY ROBINSON, FRED J. KINSEY. 

